1. Field of the Invention
Embodiments described herein relate to thermal processing in semiconductor manufacturing. More specifically, a lamp assembly, and methods of operating the lamp assembly, are described.
2. Description of the Related Art
Rapid thermal processing (RTP) systems are employed in semiconductor chip fabrication to create, chemically alter or etch surface structures on semiconductor wafers. One such RTP system, as described in U.S. Pat. No. 6,376,804, includes a lamp assembly located on the semiconductor processing chamber. The lamps are disposed in recesses of the assembly and covered with a window to isolate the lamps from the processing environment of the chamber.
As the lamps are operated, trace carbon compounds adventitiously introduced into the space around the lamps may deposit and/or decompose on the lamps, leaving a carbon residue that darkens the lamps over time. Moreover, as the lamps heat and cool during process cycles, the carbon residue may accumulate on lamp walls causing overheating which ultimately cause early failure of the lamps. It is not uncommon for lamps to become unusable less than 24 hours after being put in service.
As semiconductor processes continually aspire to higher efficiency and lower cost, there is a need to improve the longevity and cost-effectiveness of thermal lamp assemblies.